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Use of orbital data for a new approach to improve irrigation management in center pivot in Brazil

Grant number: 20/08365-1
Support type:Scholarships in Brazil - Post-Doctorate
Effective date (Start): December 01, 2020
Effective date (End): November 30, 2022
Field of knowledge:Agronomical Sciences - Agronomy - Agricultural Meteorology
Principal researcher:Fabio Ricardo Marin
Grantee:Ivo Zution Gonçalves
Home Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil

Abstract

Reliable methods to map evapotranspiration (ET), on a daily time scale and covering large areas, is still a major challenge. However, with the new models using orbital data through remote sensing approach, it became possible to estimate ET to be used in irrigation management. At the same time, new approaches to increase water use efficiency for irrigation is essential, especially in areas with high water demand. Thus, this proposal aimed to use ALEXI two-source model which has an ET product estimated at 375 m resolution and can be downscaled to 30 m with the PyDisALEXI algorithm, being sharp enough to be used even in small agricultural areas. In addition, this project also brings a new approach to estimate water demand for agricultural crops according to Marin et al. (2019) and Marin et al. (2020) suggesting to estimate the irrigation depth based on the last three days prior to the irrigation event, because under conditions of high atmospheric water demand, the crop coefficient (Kc) is lower than that suggested by FAO (Allen et al. 1998). Based on this approach, it is expected to estimate the water demand for agricultural crops of corn (East of Goias State), soybean (West of Bahia State) and sugarcane (Northwest of São Paulo State) for the period from 2013 to 2020 based on Marin et al. (2020) and, compare the results to the approach suggested by Allen et al. (1998). So, ALEXI model will be used and downscaled to 30 m resolution using PyDisALEXI. Thus, with the effective calibration for the crops under study and application of the model together with the new approach proposed by Marin et al. (2020), it is expected greater water use efficiency for irrigation, in addition to greater water use productivity, compared to the approach for irrigation management suggested by Allen et al. (1998). (AU)